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@nitrl i tstrs @anni @man inthe principles of construction.

Leners P aam No. 79,684, ma .my 7, 1868.

Immerso' TOOL-HOLDER; 1

titte rlgemlerrferrrh in in tigen Enters tte'ut mit making nu ni thetime.

To 'ALL wIIoM I'r MAY ooNoERN:

Be it known that I, WILLIAMIRMT, of the city and county of Providence,and State of Rhode Island,

have made certain Improvements' in Tool-Holders, or stoclrsg'for-thecutters of engine-lathes and planing machines; and in order that othersskilled mayunderstand the nature of my invention, I give the' followingdescription thereof, illustrated by the accompanying'drawings, andreferred to vin 'these `specifications by the letters and figures markedthereon. v

` 4Descrz'ptz'on of Drawings. l

Figdre 1 is a view, mostly in longitudinal .vertical section, with acutter inserted ready for use.

Figure 2 is a top view of the same with the cutter omitted.

Figure 3 is a side view o f theholder-with cutter.

The same letters refer to thesame parts as seen in all theV figures.

A is a bar of iron or steel, of suitable size for the`tool-postoftl1emachine for which itis to be used. @his bar is planed ormilled equally,and straight aswell as parallel on its four sides. ne end of this liscut-at a suitable angle for the insertionof the cutter, so that thepointof this ovrhangs `the hase in such degree that it may be brought to thework without-interfering with, the. stock, and also to give'a suitableangle to the point of the cutter. v

The bar A has a. mortise -through the chamfered-or angular end, and (asshown, in #he drawing) placed diamond-wise in its relationto the sidesof the holder. Abar ot'r steel, B,.is ttedsnugly to this mortise, sothat it. wi1l move up and down, and yet withoutplay,'heffere'the-tightening-device is brought to bear upon it.

The' means of tightening the cutter and-holding it rmly in place arenext to be described. v .After the bar A is iinished, (so far as theshaping'ot'` thesides and ends, and thebroaching of the mortise truly toreceive the cutter,) a hole is drilled throughl the bar A, andeountersuuk on the under side to receive the headed screw-bolt G, thehh'le in the'bar, which receives the shanlg of the screw, lbeing madelarge enough to allow of a little free motion, while the headis snuglytted, and ,preferably alittle tapering. nut, D, is itted to the upperend of the screw-bolt C, underneath which is the washer E.

A fter these parts are all fitted, the bar A isslotted at c c, aboutmidway of the perpendicular section, far

hack enough to allow the screw-bolt C 'and the nut D to spring and holdthe angular ends of the holder a little nearer togetherthan they 4wouldbe without this force applied,

It will be seen that if the tool or cutter B is accurately tted to themortise, the bringing together .of the` slotted end ofthe bar will holdit firmly for work. To raise the tool, or'to lower it, or to removeitaltogether,

-t is onlyl necessary to release' thernut D, and the-spring of the partswill allow it toslipagain in the mortise. The diierent views in Figure 4show a-modilication of' the parts,Y inform and position, without anychange,

Thesame letters refer tol like parts in these as in the drawings alreadydescribed.

The screw-bolt D'in this` view is placed at the saine angle as thecutter,v and instead of havingan ordinary. screw-bolt head, has oneshaped. as seen in side view in the'holder in section, and also detachedin a back view. This head'isa semicircle, with two smallersemicircu-lar4 trunnions.l The seating of this head 4is Vmilled out on'the under side of the 'bar A, ofjustthe size of the parts of the head,s'o 'that while only the SemcrcuIar trun nions appear onv the snrfaceiofthe bar, yet the bearing is upon the Alarger semicircle as well.

The nutl) has a seat milled'or-counterslink l-in the upper face of thecutter-holder'A, at right angles, as

regards the seating, with` the screw-bolt C.V This' throws thennt'further forward on the lhar than wherethe holt runs perpendicular-lythronghlthe bar. t lThe slot cc may be varied in directiomand positionto suit the `hind of holder for special machines. ,This variati-cuisrepresented bythe'red lines inythis ligure. i

I am aware that various devices have been Lin existence fortool-holders, both patented-and unpatented, but

they fasten-the cutter inl an entirely ditl'eijen't manner, and -bymeans .much more complicated; and in instruments of this class,simplicity of manufacture, few parts, and those o'f forms easily made,is a very desirable object.

` Therefore, While I make no claim to a tool-holder in which. the cutteris fastened by means of gibs and wedges or screw-gibs, nor to atool-holder" in which the cutter is held by means of clamping the twosides of the holder together against the cutter, as in stocks where the.bar is slotted perpendicularly in line with the cutter,

lI do not conne myself to theexact forms'of all the parts described; forinstance, the two limbs of the slotted end ofthe holder or bar may besprung slightlyapart by means of a set-screw working through one limb ofthe slottedb'arv and abutting-against the other, as seen in red lines iniig. 3, the practical 'eect being the same; hence,

lWhat I claim sv y A. tool-holder, carrying an independent cutter, for.engine-lathes and planing-machines, in which the bar or stock A isslotted transversely to the vertical line of the-cutter, dividing themortised end of the bar A into an upper and lower limb, and-thefastening'of the cutter by drawing .these limbs together with a.screw-bolt and nut, or by spreading them apart by ymeans of a set-screwpassing through one limb and abutting against the other, all made andoperating substantially as described, or their mechanical equivalents.

i WM. PRATT.

Witnesses WM. H. BAN, SAMLVH. ANTHONY.

